
body {
    background-color:white;
    font-size: 16px;
    width: 100%;
    #header{
        position: relative;
        >.back{
            font-size: 40px;
            line-height: 25px;
            color: white;
          float: left;
        }
        >.title{
            position: absolute;
            display: block;
            color: white;
            font-size: 20px;
            line-height: 25px;
            left: 50%;
            top: 50%;
            transform: translate(-50%,-50%);
        }
        >.app{
            float: right;
        }
      }
      nav{
        margin: 0 auto;
        width: 290px;
          >div{
              border:2px solid #ccc;
              background-color: #eeeeee8f;
              display: inline-block;
              padding: 10px 10px;
            //   margin-right: 5px;
              margin-bottom: 5px;
          }
      }
  }
  